The Texas Department of Agriculture (TDA) imposed a temporary, emergency quarantine on shipments of Mexican Fan and Queen Palms into Texas from Florida due to the threat of Fusarium wilt.
The temporary quarantine will remain in effect until TDA is confident Florida’s standards of testing are sufficient enough to protect our industry from the spread of this disease.
"The Department believes that immediate action is necessary to prevent the introduction and spread of this fusarium wilt from infested palms to commercial palm nurseries, production areas and landscape palms of Texas through the importation of queen and Mexican fan palms from infected areas," wrote the TDA in its emergency quarantine notification.
Fusarium wilt first broke out in Florida in 2010 and is currently widespread throughout most of the state. The mode of spread of this disease to mature landscape palms remains unknown, but is suspected to be via airborne spores. Laboratory diagnosis using molecular techniques is required to confirm the fusarium wilt fungus.
The fungus produces short-lived spores and long-lived chlamydospores that apparently can live in the soil or in infected plant tissue for years. The disease typically causes yellowing or browning on one side of the rachis of the lower leaves of palm, resulting in one-sided wilt while the other side may stay green. Reddish-brown or darkbrown streaks develop on the petiole and rachis on the affected side of desiccated or dead leaflets. Eventually, the entire leaf dies and hangs around the palm trunk. The disease progresses towards the top, wilting the younger leaves. The fungus causes a vascular wilt, obstructing water conducting xylem tissue, which results in leaf wilt, decline and death of the infected palms.
In 2013, Fusarium wilt was identified in a Mexican fan palm sample received from a dying landscape palm in Harris County, Texas, by Texas A&M AgriLife Extension Service. However, there have been no confirmed cases in Texas since then.
During November-December 2015, the TDA collected a total of 31 samples from symptomatic palms at nurseries and in landscapes in Cameron, San Patricio, Harris, Hidalgo and Cameron counties; all samples tested negative.
TDA and Texas A&M AgriLife Extension will continue to test suspect samples here in Texas.
— Compiled from TDA press releases & information.